Growth And Production Of Various Wheat Genotypes At Various Peg Concentration In Hydroponic

Wheat is a sub-tropical cereal that can be planted in the tropics, on the highland with altitude >1000 m asl. The development of wheat in the highlands compete with horticultural crops, so the creation of tropical wheat that is adaptive to lowland and drought tolerance is an alternative problem-solving. The aims of this study is to test the generation and to screen three type of mutant that is adaptive in lowland with high temperature. The study was conducted at Tamalanrea Jaya, Tamalanrea regency, Makassar province from May to August 2017. The research was conducted on hydroponic media in the plastic house (green house) at altitude <800 m asl with an average temperature of 28oC (morning) and an average temperature of 33oC (afternoon). The study was used split-plot design with the main plot of polyethylene glycol (PEG), ie 0%, 5%, 10%, and 15%; the plot was 15 wheat genotypes. The results showed that the addition of PEG concentrations at 5%, 10% and 15% decreased the crop yield by 35.91%, 55.63%, and 71.83%. Adaptive and potential genotypes developed in lowland with dry climatic conditions are genotype N.200 2.4.B.6 and genotype N.300 4.3.6


B. Methodology
The study was conducted in Tamalanrea Jaya, Tamalanrea Regency, Makassar Province from Mei to August 2017. The study was done by using Hydoponic media in the gase house at 800 m asl with average temperature 30-37 C. The study used split-plot design with the main plot of polyethylene glycol (PEG) are 0%, 5%, 10%, and 15%; plot used are 15 wheat genotypes such as :g1 =N.350 3.6.2 , g2 =N.300 3.6.1, g3 = N. Seedling with a height of 10 cm were transferred to charcoal + chocofit media on net pots with flannel axis at hydroponic installation. Hydroponics Media was added with AB Mix with the concentration of 1000 ppm. PEG treatment was aplied 2 weeks after planting with the concentration of 0%, 5%, 10%, and 15%. The pH of the solution was adjusted at 6.5; PH measurements were performed using pH meters. Volume of water for one treatment installation was 250 liters. Subsequent maintenance was done by adding nutrient solution daily according to the amount of water volume decrease from 150 liters; to maintain PEG concentration in the media during treatment.
The parameters observed in this study were plant height, the percentage of empty floret, number of spikelet per panicles, the period of seed filling (Seed Replenishment), yield per clump, and stress tolerant index (ITC). The ITC is calculated based on seed production using the formula proposed by Fischer & Maurer (1978): ITC = (Ypi x Ysi)/Yp 2 Where: Ysi: The average of a genotype suffered drought stress Ypi: The average of a genotype without drought stress YP: The average of the total of genotype that not suffered drought stress The criterion for to determine the tolerance level for drought stress is; the value of ITC≤0.5=sensitive, 0.5 <ITC≤1.0 = medium, and ITC> 1.0 = tolerant.

C. Result and Discussion 1. Number of spikelet and the period of seed filling (Seed Replenishment)
Statistical analysis showed that the genotype had a very significant effect on the number of spikelets, plant height, and seed filling duration. The results of LSD Test in Table 1 show that the genotype g10 (N.  The treatment with different PEG concentrations to the wheat mutants may show different plant responses even though they are placed on the same plant medium. Treatment of PEG concentrations in wheat crops may have water deficiency, cell damage, turgor loss, closed stomata, early reaping on plant leaves, disturbed gas exchange and lead to not optimum growth and production of wheat mutants. This is because the ability of PEG to hold water components so that enough water are enable for plants for metabolism activities, thus impact on growth and development of the plants. The parameter affected by the plant experiencing drought stress is plant height, the number of spikelet, the duration of seed filling and the percentage of empty florets; these significantly correlated to the production. Based on the results obtained from the observations with treatment without drought stress; treatment of PEG concentration at 5%, 10%, and 15%; the wheat mutant showing the best response with the highest yield was the wheat mutant g10 (N.200 2.4.B.6) The high performance of wheat stems is very important in determining the high production genotype as it affects the vulnerability of the plant to fall. The height of the wheat crop has decreased with increasing level of PEG concentration. The decrease of plant height is caused by the lack of water uptake by plant so that the metabolic process of the plant does not occur maximally, this may lead to a lack of energy generated for cell division, premature leaf aging and stunted growth of plant height; PEG in the hydroponic solution media results in the inhibition of root formation of plants since PEG is able to attach to the roots of wheat and thereby inhibiting the water uptake by the plants hence affects the formation of roots is not maximal. Salisbury & Ross (1992) revealed that high concentrations of PEG inhibit the division and development of the cell.

Number of Productive Tillers
Statistical analysis shows that the interaction between genotypes with PEG concentrations had a very significant effect on the percentage of empty florets. LSD test in table 2 shows that g8 (N.250 4.6.2) gives the highest number of productive tillers at treatment with PEG concentrations of 0% and 5% and is significantly different from the comparison varieties of Nias (a) and Munal (b), whereas g6 (N. 3503.1.4) shows the lowest percentage of empty florets at 10% PEG and 15% PEG concentrations and significantly different on the comparison varieties of variety Nias (a) and Munal (b). The number of spikelet is a vegetative parameter in wheat plants that can be easily observed and is related to the production of wheat crops. The correlation regression test showed that the number of spikelet has no effect on the production yield with the value of 0.01. It is caused by the slight amount of food and the assimilates which will fill the spikelet so that the number of filled spikelet is less than the number of empty spikelet. This is supported by the opinion of Wahid, Gelani, Ashraf & Foolad, (2007) which states that wheat suffered drought stress (deficit water) impact on assimilating forming process; that will be inhibited as the filling of floret in spikelet is not optimal.

Yield
Statistical analysis shows that the interaction of genotype treatment with PEG concentration had a very significant effect on the crop yield. The LSD test in Table 3 shows that genotype 10 (N.200 2.4.B.6) has the highest production and is significantly different from the comparison varieties of variety Nias (a) and Munal (B) and is tolerant to all PEG concentrations. The condition of drought stress in wheat crop can lead to the faster flowering and harvest ages, of which the early cross flowering and harvest time resulted in the duration of the seed filling which become not optimal and the decrease of seed production per panicle. This is the mechanism of plants in response to the drought stress so that flowering and harvesting age become faster. According to Stapper & Fischer (1985), during the seed filling process the higher temperature affects the faster development of wheat; although the plants are optimally managed, it can decrease to 4% for temperature rise of 1°C at high temperatures due to the seed filling period become very short.
One response to wheat crops suffered drought stress is the increase in the percentage of empty florets. The percentage of empty florets is the number of empty space found in panicles as the accumulation of assimilates that will fill the panicle is not sufficient, this is due to the not optimal process of photosynthesis so that the assimilate is formed slightly, and in the end the percentage of empty floret is greater than the number of seeds per panicle. The percentage of empty florets in wheat plants is an indicator that wheat crops are tolerant or not to the stress condition. Simmons; Anderson; in Akbar (2016) stated that too low or too high temperature resulting in the number of sterile florets that cannot be fertilized.
The treatment of PEG in the hydroponic solution will hold water component, impacts water uptake by plants and thereby causing drought. According to Levitt, (1980) drought stress is due to a lack of water supply from the root zone and excessive water demand by leaves; where the period of evapotranspiration exceeds the length of water uptake by plant roots. This will impact on the decline in photosynthetic activity, so the amount of assimilates produced decreases and causes the formation of panicles and the filling of seeds will decrease. Oertli (1985) states that the polyEthylene Glycol Compound is able to stimulate the drought stress condition by decreasing the potential of water present in the root environment and resulting in the decrease of hydrostatic pressure in the cell. This is in line with the opinion by Taiz & Zeiger (2002), that drought stress affects plant morphology and decreases crop yield.

D. Conclusion
The genotype of wheat mutant that potentially adaptive with high yield in hydroponic media at the treatment of without PEG, 5%, 10% and 15% PEG concentration, are N.250 4.6.2 and N.200 2.4.B.6. The characters of seed filling and the percentage of empty floret have a positive correlation to the crop yield.